JPH0673764B2 - Manufacturing method of hard metal or ceramic drill intermediate product and extrusion press tool - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a drill intermediate product made of hard metal or ceramic, which has at least one water injection hole extending spirally therein. A method for producing a drill intermediate product, which comprises pressing a hard metal or ceramic heated to an extrusion press temperature through a chamber formed by a mandrel and a nozzle, during which the intermediate product is pressed. It relates to a helical twisting type and to an extrusion press tool for carrying out the method, which has a mandrel and a nozzle.

2. Description of the Related Art The above-mentioned drill intermediate product made of hard metal or ceramic and its extrusion press manufacturing method are disclosed in European Patent Publication No. 011803.
It is known from specification No. 5. Furthermore, in the intermediate product produced by helical twisting in this known example, the chip chamber must also be ground, which results in considerable costs. In order to manufacture a nozzle tip made of hard metal, on page 10 of the above-mentioned known example, it is proposed to extrude a cylindrical sintered metal intermediate product by an extrusion press device having a press forming nozzle. ing.

The spirally extending cooling passage is formed by twisting the sintered metal intermediate product ejected from the extrusion press with an angular velocity defined according to the material flow and the desired drill shape and spiral shape of the cooling passage. Manufactured in a known twisting device, continuous and uniform axial guidance of the sintered metal intermediate product and likewise a continuous and constant twisting movement are carried out.

The disadvantage of this prior art is therefore the need for an additional twisting device and a corresponding control and adjustment mechanism in addition to the extrusion press tool.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a manufacturing method for a hard metal or ceramic intermediate product which requires as few grinding operations as possible in subsequent processing for manufacturing a drill, for example to form a chip chamber. And in an extrusion press tool, to produce the above-mentioned intermediate product with exactly uniform pitch and uniform water hole diameter without the need for additional working steps and twisting, control and adjusting equipment and the like.

Means for Solving the Problems (Method and Manufacturing Tool) The above-mentioned problems are, in the manufacturing method of the present invention, a continuous molded product obtained by arranging a single or a plurality of spiral webs on the inner jacket wall of the die or Through the groove or grooves, in the direction of the extrusion press guide, during this pressing step, the desired water injection hole diameter or diameters fixed to the mandrel ending short of the nozzle inner chamber ( And optionally with a desired spacing between each water injection hole) and by thrusting a central pin of elastic material into the nozzle, and in the extrusion press tool according to the invention, the nozzle inner sleeve The wall has at least one web or groove extending helically in the pressing direction, and the mandrel terminating in front of the nozzle inner chamber is provided with one or more elastic central pins with the desired water inlet diameter. And place in each water injection hole This was solved by the fact that it was fixed at the desired distance and this central pin was thrust into the interior of the nozzle.

EFFECTS OF THE INVENTION (Method and Manufacturing Tool) According to the present invention, instead of twisting the sintered intermediate product after being ejected from an extrusion press device as in the conventional case, twisting and production of water injection holes are performed together with an extrusion press. Guaranteed to be done in-process. By means of each elastic central pin arranged on the mandrel of the extrusion press tool, i.e. in its diameter during twisting, it is possible to form a suitable water injection hole, which is evenly distributed. The shape is not damaged in the subsequent working process. The twisting is independent of external parameters such as the material flow velocity in the extrusion press, since the twisting takes place at the same time as the extrusion press via one or more guide webs or grooves. Regardless of how much punch the material is pushed into and through the nozzle, a uniform pitch is formed in the hard metal or ceramic drill intermediate product. The groove dimensions of the intermediate product or the pitch dimensions of the web advantageously define the pitch of the chip chamber, which can be different for each drill type, and in extreme cases even straight grooves. . In order to be able to produce different webs or groove pitches or intermediate products with different diameters with the same method or with the same extrusion press tool, only the replacement of the nozzle is necessary. Unless this is the case, no other adjustments or adjustments are necessary.

Embodiments (methods and production tools) The uniformity of the pitch is even greater if the guidance is carried out via the aforementioned web helix of at least 90 ° or more, preferably 180 ° or more. For mechanical and manufacturing and process engineering reasons, this guide part, i.e. the web or the groove, preferably has a semi-circular cross section and a radius of at least 0.2 mm.

Experiments have also shown that it is advantageous to choose the helix angle of the spiral web or groove in the nozzle to be somewhat larger than the desired angle for the intermediate product. The degree is generally 3 ° to 7 °.

If each central pin is supported by a spacer at the height of the nozzle inlet chamber, the constancy of its extension parallel to each other or to the annular groove or web is further increased.

The central pin is preferably formed elastically so that its forced twisting during twisting of a hard metal or ceramic press can be overcome without damage, preferably an alloy of copper or non-ferrous metal. A light metal and / or an iron and / or iron alloy and / or aluminum or a light metal alloy, and in particular a plastic such as polyamide, may be used.

Depending on the intended use of the drill to be produced from this intermediate product, it is also advantageous to have different diameters for each water injection hole. In such cases, a mandrel with a correspondingly dimensioned central pin is used.

With regard to the good flowability of the pressed material, it is advantageous if the mandrel has a generally conical taper on the side facing the nozzle, with a resilient central pin projecting from the conical jacket. This conical shape ends at one point or transitions into a generally cylindrical spacer for the support of the central pin.

The extrusion press tool according to the invention comprises a (replaceable) nozzle with at least one web or groove extending helically in the pressing direction, and a mandrel which ends before the inner chamber of the nozzle. An elastic central pin having the desired water injection hole diameter or diameters is fixed to the. The central pins are fixed on the side of the mandrel facing the nozzles with a distance to be formed between the respective water injection holes to be manufactured, and project into the nozzle inner chamber. Each of the central pins is preferably formed so as to reach the end of the inner chamber of the nozzle, and further protrudes by 1 to 2 mm. Also, the groove or web should be 90 ° or more when projected, preferably 18 °.
It may be formed with a helix of 0 ° or more. This extrusion press tool also has the same simple structure as the known tools, but it is advantageous because it does not require the additional twisting device required by conventional extrusion press tools. Further, for reasons of manufacturing technology, the nozzle or web shape described in claim 7 is advantageous.

EXAMPLE The hard metal drill intermediate product shown in FIGS. 1a and 1b has two helical grooves 1 with semicircular walls, the radius r of which is 1 It is a value of 1 mm. Each groove 1 is a so-called "preformed" chip chamber, which is subsequently completely ground for the production of drill tips. Furthermore, this hard metal drill intermediate product has two water injection holes 2, the diameter of which is 0.8 mm and extends parallel to the groove 1. What is the connection wire for groove 1 and the connection wire for the water injection hole?
An embodiment having an angle of 90 ° and, in contrast, an angle r of 0 ° is shown in FIG. 1c. Any angle value between these two angles is possible, and eccentric arrangements are possible in which both water injection holes are located on opposite sides of one virtual cross-section centerline.

From this drill intermediate product, a member of suitable length for the production of the drill tip is cut and the chip chamber (cutting lip) is ground to form the drill tip, at which point both water injection holes are formed. It's over.

The extrusion press tool according to the invention shown in FIG. 2 consists essentially of a nozzle 3, an insertion nozzle 4, a mandrel 5 and a nozzle frame 6 arranged in front of this nozzle. The nozzle 3 is shown in FIGS. 5a and 5b, and the nozzle frame 6 is shown in FIG.
It is detailed in the figure. The nozzle 3 is formed from a cylindrical ring with a cylindrical nozzle inner chamber 7 bounded by an inner surface 8 of the jacket wall. The inner surface 8 of the nozzle jacket wall has two webs 10 spirally extending in the pressing direction 9,
This web 10 has a 1/4 circle (90 °) over the nozzle length 1.
Is formed. Each semi-circular web in cross section has a radius of at least 1 mm. The nozzle 3 shown in FIGS. 5a and 5b has the insertion nozzle 4 shown in FIG.
Has been placed in front. This insert nozzle 4 has a conical insert hopper for the press blank, the minimum radius of the hopper corresponding to the radius of the insert nozzle 4. The opening angle α of the insertion hopper 4 is about 70 °.

A mandrel 5 is arranged so as to be axially centered with respect to the insertion nozzle 4 and the nozzle 3, and the tip of the mandrel 5 is located almost immediately before the nozzle inner chamber 7. The mandrel 5 has, for example, the shape shown in FIGS. This mandrel 5 has a conical part 13 in addition to the cylindrical part 11 and the base part 12, and the center pin 14 projects from the conical part outer surface 13a in parallel to the pressing direction, or the mandrel tip has a cylindrical shape. Is connected to a spacer 15 in the shape of
Each central pin 14 running parallel to the conical (trapezoidal) partial mantle surface 13a is arranged to contact the spacer 15. The preferred angle β of the cone is 40 °.

The above-mentioned members are arranged in the nozzle frame 6 by a known method.

Next, the method according to the present invention will be described.

By means of a punch, not shown in FIG. 2, a hard metal block is pressed in the direction of the arrow 9 into the chamber 16 formed between the mandrel 5 and the nozzle frame 6 and on the basis of the subsequent pressing movement. It is pushed into the chamber 17 of the inlet nozzle 4, where the hard metal is compressed. Original molding is carried out in two stages inside the nozzle inner chamber 7. Subsequent feeding of the punch gives the hard metal a cylindrical shape, whereby the web 10 forms a spirally extending groove in the peripheral surface of this hard metal continuous molding, whereby at the same time. The molded product extruded from the nozzle 3 is swung around its longitudinal central axis. Due to this swiveling, the elastic central pin, which penetrates the nozzle inner chamber 7, does not form a cylindrical hole corresponding to its wire diameter, as in the case of non-rotating guides for moldings, but also spirals. Twisted and correspondingly helically extending water injection holes 2 are formed, which water injection holes 2 extend parallel to the groove 1. The mutual distance between the center pins 14 is formed according to the distance between the water injection holes extending in parallel with each other.

The hard metal drill intermediate product shown in FIG. 7a has two, helically extending webs 18 having walls of semi-circular cross section, the radius r of which is 1 mm. The other part is 1a, b
It corresponds to the above-mentioned hard metal drill intermediate product shown in the figure.

FIGS. 8a, 8b show an insertion nozzle different from the above-mentioned nozzle shown in FIGS. 5a, b, which insertion nozzle comprises two grooves 19 extending spirally in the pressing direction 9. The inner surface 8 of the nozzle sleeve, the groove 19 forming a quarter circle (90 °) over the nozzle length 1.

[Brief description of drawings]

The drawings show an embodiment of the present invention, in which FIG.
FIG. 1b is a side view and an end view showing a drill intermediate product having a groove and a water injection hole formed by machining, FIG. 1c is an end view of a drill intermediate product according to another embodiment, and FIG. 2 is a cross section of an extrusion press tool. FIG. 3 is a sectional view of a conical mandrel, FIG. 4 is a sectional view of a mandrel with a cylindrical spacer, FIGS.
FIG. 5b is an end view and a cross-sectional view of a nozzle having a spiral web, FIG. 6 is a view showing a inserting nozzle which is arranged in front of the nozzle, and FIGS. 7a and 7b are processed webs and water injection holes. A side view and an end view showing a drill intermediate product having
8a and 8b are an end view and a sectional view showing a nozzle having a spiral groove. 1,19 …… Groove, 2 …… Water injection hole, 3 …… Nozzle, 4,6 …… Slotted nozzle, 5 …… Mandrel, 6 …… Nozzle frame, 7…
… Nozzle inner chamber, 8 …… Nozzle sleeve inner surface, 9 …… Press direction, 10,18 …… Web, 11 …… Cylindrical part, 12 …… Stand part, 13 …… Conical part, 13a… Conical part Mantle surface, 14 ……
Center pin, 15 …… Spacer, 16,17 …… Room

Claims (13)

[Claims] 1. A method of manufacturing a drill metal intermediate product made of a hard metal or ceramic, comprising at least one water injection hole spirally extending inside, and a spiral groove or web extending on an outer peripheral surface parallel to the water injection hole. The hard metal or ceramics heated to the extrusion press temperature is passed through the nozzle,
Extrusion in the form of helical twisting along at least one web or groove spirally arranged in the nozzle inner chamber and along at least one wire-shaped central pin penetrating into the nozzle inner chamber At least one that initially extended in a substantially straight line by twisting the press material
A method for manufacturing a drill intermediate product made of hard metal or ceramic, characterized in that two central pins elastically follow the twisting motion and are deformed and held in a spiral shape. 2. A method according to claim 1, wherein the extruded press material is spirally guided through at least 90 ° in the nozzle. 3. The method according to claim 1, wherein the guide is provided by a web having a semi-circular cross section or a groove having a semi-circular cross section having a radius of at least 0.2 mm. Production method. 4. The method according to claim 1, wherein the spiral angle of the spiral web or groove is selected to be somewhat larger than the desired spiral angle for the intermediate product. Production method. 5. The manufacturing method according to claim 1, wherein the center pin is supported by a spacer at the height of the nozzle inlet chamber. 6. A hard metal or ceramic drill intermediate product having at least one water injection hole extending spirally therein and a spiral groove extending parallel to the water injection hole on an outer peripheral surface. An extrusion press tool comprising a nozzle having an inner sleeve having a spiral web extending in the pressing direction, and a wire-like member penetrating into the nozzle inner chamber and fixed in front of the nozzle inner chamber in the pressing direction. An extrusion press tool for producing a hard metal or ceramic drill intermediate product, characterized in that each central pin consists of an elastic material. 7. A nozzle and a center pin having a length (1) at least set such that the web (10) or groove (19) draws a spiral of 90 ° or more. 6
Extrusion press tool according to the item. 8. Extrusion press tool according to claim 6 or 7, characterized in that the cross section of the web (10) or groove (19) is semi-circular with a radius of at least 0.2 mm. 9. The method according to claim 6 or 7, wherein the central pin or pins are made of an alloy of copper or a non-ferrous metal.
Extrusion press tool according to the item. 10. Extrusion press tool according to claim 9, characterized in that the central pin or pins made of metal or metal alloy are coated with polyamide. 11. Extrusion press tool according to any one of claims 6 to 10, wherein each central pin (14) has a different diameter. 12. A mandrel (5), wherein the side facing the nozzle (3) is tapered in a substantially conical shape, and the central pin projects from the conical outer surface (13a). The extrusion press tool according to any one of claims 6 to 11. 13. Extrusion press tool according to claim 12, characterized in that the conical taper tapers into a substantially cylindrical spacer (15) for the support of the central pin (14).